The wrist is a bio-mechanically complex joint allowing the wrist to move in extension (up), flexion (down), radial deviation (towards the thumb), ulnar deviation (towards the small finger) and minimal degrees of rotation. view

Compartment syndrome in all extremities is an orthopedic emergency. The hand muscles are covered and divided by groups into compartments by a well defined, unyielding envelope called the deep fascia. view

An amputation is the severing of a body part. Amputations are classified as partial and complete and if the amputation was a clean cut, a crushing amputation or an avulsion amputation where the amputated limb is pulled right off of the body. view

The most frequent swelling or masses found at the hand and wrist level are ganglion cysts. view

NERVE & VESSEL…

Pathology

Nerves are cables that transmit impulses from the brain and spinal cord that give specific orders to the various body parts. There is a spectrum of nerve injuries depending on the mechanism of injury that have been classified into five grades according to the severity by Dr Sunderland. Grades I and II are minor injuries that will recover function within weeks of the injury without the need for surgery. Grades IV and V represent a more severe injuries that requires surgical intervention for function to be recovered. Grade III has variable results and often requires surgery with a careful evaluation intraoperatively for the various treatment options.

Once a nerve is cut and subsequently repaired, the distal portion of the nerve dies, leaving an empty tube where the regenerating nerve re-grows from the point where the injury occurredto the end of the final target organ. In addition, if the final target organ is a muscle, there is only a certain amount of time available for the nerve to reach the target organ and provide function before it is too late. If this does not happen within an average of six months then the muscles atrophy permanently. Sensory nerves have a more prolonged time frame to reinervate and have the terminal sensory organs regain full sensory function that can be a few years.

Vessels are the pipes where the blood flows through. Their purpose is to supply blood that carries oxygen and other nutrients to the multiple tissues in the body. Tissues survival depends directly on sufficient blood supply being delivered depending on the dynamic oxygen requirements of the various tissues. The vessels that carry the blood from the heart to the periphery are called arteries. The vessels that bring the blood back from the periphery to the heart are called veins. The vessels branch pretty much like a tree from the heart to the periphery. At the level of the wrist there are two main arteries that supply most of the blood for the hand. Two main veins exist that when injured or occluded, will have new veins regenerate as long as the hand has at least one sufficient vein for outflow. When a vein is injured, the blood flow is interrupted and the blood loss can be sufficient enough to risk a person’s life. If only one artery is injured, the other artery if normal has sufficient blood supply to keep the tissues alive in the hand. On occasion, one artery may not be sufficient to provide enough blood supply to the whole hand because of underlying disease and in this instance, ischemia and tissue necrosis with loss of digits will occur. When the two main arteries have been transected about the wrist, it is imperative to re-establish blood flow in a timely fashion to prevent tissue death.

Treatment

Nerve and Vessel (arteries and veins) lacerations about the hand require repair with microsurgical techniques that involve the use of magnification with a microscope, special instruments called jewelers instruments and very fine suture that cannot be handled by the naked eye. The use of a microscope results in accurate repairs and excellent functional outcomes. These techniques require a fellowship in special microsurgery training done in many hand surgery programs. Although a plastic surgeon has microsurgical training, they are not trained to fix or reconstruct complex injuries requiring, bone, tendon, nerve, artery, and vein repairs. This holds true for orthopedic surgeons and general surgeons.

A nerve repair will take approximately 4 weeks for the new axons (nerve fibers) to cross the line of repair and then continues advancing at a pace of approximately 1 mm a day. Therefore, if a nerve laceration that has occurred at 10 cm proximal to the final target organ, will take approximately 100 days plus 30 more days from crossing the repair line for a total of 130 days to reach the final target organ and regain full function. The outcome for nerve repair is influenced by technical factors including; a tension free repair, proper fascicular alignment, appropriate bed, age less than 35 years, health status and smoking habits amongst others.

A vessel repair or reconstruction can be done with several techniques; however, the principles of microvascular surgery should be followed. The average percentage of success in small vessels is 95- 97 %. Patients that have had a vessel repair may have to remain in the hospital for 5 days with blood thinners and other measures to help the vessel repair remain patent.

The nerves and vessels once repaired will require of initial protection in a splint followed by early, progressive and carefully supervised motion by a hand therapist. Therapy geared to nerve repairs will include other different modalities such as nerve glide exercises, desensitization, neuromuscular re-education, bio-feedback, functional electric stimulation, sensory re-education, strengthening and splinting as indicated.